#[macro_use]
extern crate lazy_static;

use lighthouse_metrics::{
    inc_counter, try_create_int_counter, IntCounter, Result as MetricsResult,
};
use slog_term::Decorator;
use std::io::{Result, Write};

pub const MAX_MESSAGE_WIDTH: usize = 40;

lazy_static! {
    pub static ref INFOS_TOTAL: MetricsResult<IntCounter> =
        try_create_int_counter("info_total", "Count of infos logged");
    pub static ref WARNS_TOTAL: MetricsResult<IntCounter> =
        try_create_int_counter("warn_total", "Count of warns logged");
    pub static ref ERRORS_TOTAL: MetricsResult<IntCounter> =
        try_create_int_counter("error_total", "Count of errors logged");
    pub static ref CRITS_TOTAL: MetricsResult<IntCounter> =
        try_create_int_counter("crit_total", "Count of crits logged");
}

pub struct AlignedTermDecorator<D: Decorator> {
    wrapped: D,
    message_width: usize,
}

impl<D: Decorator> AlignedTermDecorator<D> {
    pub fn new(decorator: D, message_width: usize) -> Self {
        AlignedTermDecorator {
            wrapped: decorator,
            message_width,
        }
    }
}

impl<D: Decorator> Decorator for AlignedTermDecorator<D> {
    fn with_record<F>(
        &self,
        record: &slog::Record,
        _logger_values: &slog::OwnedKVList,
        f: F,
    ) -> Result<()>
    where
        F: FnOnce(&mut dyn slog_term::RecordDecorator) -> std::io::Result<()>,
    {
        match record.level() {
            slog::Level::Info => inc_counter(&INFOS_TOTAL),
            slog::Level::Warning => inc_counter(&WARNS_TOTAL),
            slog::Level::Error => inc_counter(&ERRORS_TOTAL),
            slog::Level::Critical => inc_counter(&CRITS_TOTAL),
            _ => (),
        }

        self.wrapped.with_record(record, _logger_values, |deco| {
            f(&mut AlignedRecordDecorator::new(deco, self.message_width))
        })
    }
}

struct AlignedRecordDecorator<'a> {
    wrapped: &'a mut dyn slog_term::RecordDecorator,
    message_count: usize,
    message_active: bool,
    ignore_comma: bool,
    message_width: usize,
}

impl<'a> AlignedRecordDecorator<'a> {
    fn new(
        decorator: &'a mut dyn slog_term::RecordDecorator,
        message_width: usize,
    ) -> AlignedRecordDecorator<'a> {
        AlignedRecordDecorator {
            wrapped: decorator,
            message_count: 0,
            ignore_comma: false,
            message_active: false,
            message_width,
        }
    }
}

impl<'a> Write for AlignedRecordDecorator<'a> {
    fn write(&mut self, buf: &[u8]) -> Result<usize> {
        if self.ignore_comma {
            //don't write comma
            self.ignore_comma = false;
            Ok(buf.len())
        } else if self.message_active {
            self.wrapped.write(buf).map(|n| {
                self.message_count += n;
                n
            })
        } else {
            self.wrapped.write(buf)
        }
    }

    fn flush(&mut self) -> Result<()> {
        self.wrapped.flush()
    }
}

impl<'a> slog_term::RecordDecorator for AlignedRecordDecorator<'a> {
    fn reset(&mut self) -> Result<()> {
        self.message_active = false;
        self.message_count = 0;
        self.ignore_comma = false;
        self.wrapped.reset()
    }

    fn start_whitespace(&mut self) -> Result<()> {
        self.wrapped.start_whitespace()
    }

    fn start_msg(&mut self) -> Result<()> {
        self.message_active = true;
        self.ignore_comma = false;
        self.wrapped.start_msg()
    }

    fn start_timestamp(&mut self) -> Result<()> {
        self.wrapped.start_timestamp()
    }

    fn start_level(&mut self) -> Result<()> {
        self.wrapped.start_level()
    }

    fn start_comma(&mut self) -> Result<()> {
        if self.message_active && self.message_count + 1 < self.message_width {
            self.ignore_comma = true;
        }
        self.wrapped.start_comma()
    }

    fn start_key(&mut self) -> Result<()> {
        if self.message_active && self.message_count + 1 < self.message_width {
            write!(
                self,
                "{}",
                std::iter::repeat(' ')
                    .take(self.message_width - self.message_count)
                    .collect::<String>()
            )?;
            self.message_active = false;
            self.message_count = 0;
            self.ignore_comma = false;
        }
        self.wrapped.start_key()
    }

    fn start_value(&mut self) -> Result<()> {
        self.wrapped.start_value()
    }

    fn start_separator(&mut self) -> Result<()> {
        self.wrapped.start_separator()
    }
}
